This letter investigates the effects of the Space-Time Block Code (STBC) transmitter diversity and Time Switched Transmitter Diversity (TSTD) schemes while simultaneously considering the time diversity effect derived from Chase combining and the frequency diversity effect for downlink Spread OFDM packet wireless access in a broadband multipath fading channel. The simulation results show that when pilot channel based channel estimation is performed, TSTD improves the required average received signal energy per symbol-to-noise power spectrum density ratio by approximately 1.0 and 0.5 dB compared to one-branch transmission, without and with antenna diversity reception, respectively, while the benefit of STBC is small due to channel estimation error, when the maximum number of retransmissions in Chase combining is three in a 12-path Rayleigh fading channel with the root mean squared delay spread of 0.3 µsec and the maximum Doppler frequency of 20 Hz.